Description
In the Linux kernel, the following vulnerability has been resolved: KVM: s390: Free guest debug data on vcpu destroy kvm_s390_clear_bp_data() is only called from kvm_arch_vcpu_ioctl_set_guest_debug(), i.e. when user space changes or disables debugging. A vCPU that is destroyed while hardware breakpoints are still armed - the normal case when the VMM just exits or crashes - leaks hw_bp_info, hw_wp_info and all old_data buffers, since generic KVM frees the vCPU right after kvm_arch_vcpu_destroy(). That is bounded by MAX_BP_COUNT entries, so roughly 8 KiB per vCPU, but it is unbounded over VM lifetimes. The allocations are GFP_KERNEL_ACCOUNT, so the charge also outlives the exiting process and pins dying memcgs. Fix by clearing the debug data on vCPU destruction. Calling it unconditionally is fine: struct kvm_vcpu is zero allocated, so for a vCPU that never enabled debugging the counters are 0 and the pointers NULL.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
27291e2165b6de70c476b7b675308113edd69a60 to < 053f2068cf9b0654b651fed5ad7649d3deb982bfaffected27291e2165b6de70c476b7b675308113edd69a60 to < 6c996b12bbe4a6023076e8eee3cfaf2cc99db76caffected27291e2165b6de70c476b7b675308113edd69a60 to < d6280fc540d8f4653c9b54a78cb747e128070f5eaffected27291e2165b6de70c476b7b675308113edd69a60 to < 544a5a665019cef394ce8bda97fa7a2cab253781affected27291e2165b6de70c476b7b675308113edd69a60 to < 9a32c4c6a6c23b7f5bf765eb5b83ba7f64a8ec63affected27291e2165b6de70c476b7b675308113edd69a60 to < b5acacfdb8966abff91836c1c5bd7da59d8a526eaffected27291e2165b6de70c476b7b675308113edd69a60 to < e4d8b7f176b976474e0800ba71ee2dfa3ce263c9affected27291e2165b6de70c476b7b675308113edd69a60 to < e7f698b09d4a7c36b299acf680fc50fe868e2bcdaffected
Linux Linux
Default version status: affected
3.16affected0 to < 3.16unaffected5.10.270 to ≤ 5.10.*unaffected5.15.221 to ≤ 5.15.*unaffected6.1.188 to ≤ 6.1.*unaffected6.6.157 to ≤ 6.6.*unaffected6.12.110 to ≤ 6.12.*unaffected6.18.51 to ≤ 6.18.*unaffected7.2.5 to ≤ 7.2.*unaffected7.3 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/053f2068cf9b0654b651fed5ad7649d3deb982bf ↗
- https://git.kernel.org/stable/c/6c996b12bbe4a6023076e8eee3cfaf2cc99db76c ↗
- https://git.kernel.org/stable/c/d6280fc540d8f4653c9b54a78cb747e128070f5e ↗
- https://git.kernel.org/stable/c/544a5a665019cef394ce8bda97fa7a2cab253781 ↗
- https://git.kernel.org/stable/c/9a32c4c6a6c23b7f5bf765eb5b83ba7f64a8ec63 ↗
- https://git.kernel.org/stable/c/b5acacfdb8966abff91836c1c5bd7da59d8a526e ↗
- https://git.kernel.org/stable/c/e4d8b7f176b976474e0800ba71ee2dfa3ce263c9 ↗
- https://git.kernel.org/stable/c/e7f698b09d4a7c36b299acf680fc50fe868e2bcd ↗